Snow/ ice making &amp; preserving methods

ABSTRACT

This invention relates to method and system for making of artificial snow or ice for outdoor as well as indoor artificial ski as well as method and systems for preserving ice for winter recreational activities, all year round for indoor facilities and at least half year or longer for outdoor facilities. It also relates to method and systems for preserving ice using embedded coolant lines capable of absorbing the heat from the thermal storage medium through a coolant and passing on same further to snow/ice layer. It also relates to method and systems for circulating waste snow/ice and using the thermal energy stored for snow making.

This application claims priority from U.S. provisional Ser. No. 61/463,970 filed on Feb. 26, 2011 for the invention titled “Indoor and Outdoor Thermal Storage, Snow and Ice Making Method”.

FIELD OF INVENTION

The present invention relates to making of artificial snow or ice for outdoor as well as indoor artificial ski slope for winter recreational activities, all year round for indoor facilities and at least half year or longer for outdoor facilities. Wherein, thermal storage unit is charged by refrigeration means. Cooling is drawn later from the thermal storage means to make snow or ice to be blown over the slope (in case of ice, crushing the ice into smaller pieces first) containing the thermal storage unit which can then keep the ice/snow cold for longer periods of time. In the alternative snow or ice can be produced in an outdoor or enclosed Air Conditioned environment.

BACKGROUND

Artificial snow slopes for indoor and outdoor skiing and other winter recreational activities have been around for years making use of various methods. Some make crushed ice while others make snowflakes, the two being completely different in structure.

Operational problems relating to making crushed ice or snow flakes in outdoor facilities have been overcome by various innovative methods in the past, for example in one method ice cubes or blocks are made by giant refrigeration units which are then crushed down to much smaller uniform size and blown over the slope. In another method ice is made in drums, as it is made scraper blades scrap the ice from the side of the drums, thereafter, the scraped ice is blow on to the slope. These methods are mostly used for outdoor slopes, having huge disadvantages in terms of very short period of time the slope can be used due to weather condition, in most cases only 1.5 to 2 months in the Western United States and maybe 2 to 3 months in the Eastern United States. Out door unconditioned spaces are heavily dependent on weather condition, i.e. wind, temperature, rain and humidity. Ice has to be constantly made on a 24 hour a day, 7 days a week basis to stay well ahead of the ice losses due to melting and evaporation. Current systems have many disadvantages.

Similarly indoor ski slopes have air conditioned envelops with temperatures maintained at about 0° C. to −5° C. (32° F. to 23° F.) most of the time and lower temperatures at snow making periods, these low temperatures must be maintained round the clock to make and preserve the snow. Using this method artificial snow can be made which is 100% identical in structure to real natural snow. To overcome the enormous refrigeration cooling loads especially during snow making periods current systems employ the use of a thermal storage unit, which reduces the size of the refrigeration unit down to ⅛ or 1/20 of what would be needed otherwise. U.S. Pat. Nos. 5,230,218, 7,124,958 and 7,269,959 describes how such massive reduction in refrigeration unit size is to be accomplished.

By charging the huge thermal storage unit to store cooling over long off peak periods it is desirable that, the massive amount of stored cooling can then be used to supply cooling through out the day especially at the huge peak cooling load demand during the snow making periods. The heart of the previous invention's thermal storage system is mixing of a good thermal conductor, i.e. Aluminum oxide or alumina into the water before it is frozen and super cooled to around minus −5° C. to −30° C. (23° F. to −22° F.) ideally at minus −20° C. (−4° F.). The aluminum oxide or alumina or any other good thermal conductor bound by ice absorbs the heat from the ice and transmits it into the embedded cooling pipes in the ice, that are in turn attached to the refrigeration unit, which are used to cool the thermal storage unit or to take cooling from the thermal storage unit during snow making periods and for air conditioning of the envelope when the thermal storage means is in the “cooling supply mode” of operation. This thermal storage method is more efficient ice only thermal storage units using only ice, which have been around for decades and do not contain any thermal conductor that would otherwise absorbed the heat in the ice and conduct it away from it via the cooling pipes, making them less efficient. But at the same time, thermal conductive material suffer from inherent drawback as they also tend to transfer cooling or absorbing heat from objects in contact with the thermal conductive material.

There is still a need to improve the efficiency of the existing methods to reduce electrical load as well as operating expense by extending the period between charging, which in turn can lead to lower Green House Gases emissions (GHG). In addition to the advantages just mentioned to some degree the proposed system can enable the use of thermal storage units in the outdoor centers.

It is the purpose of the present invention to overcome the current problems thereby, making the crushed ice or snow more resistant to melting due to weather conditions resulting in longer operating periods, while drastically reducing operating costs through energy efficiency.

It is further desired to keep the outdoor and indoor thermals storage means colder longer with a lower amount of energy input as opposed to current systems to enhance the energy efficiency of the thermal storage means.

This is where the present invention comes in and lends its advantages.

SUMMARY OF THE INVENTION

In response to aforementioned the present invention realized the need for a method that is far more efficient then the current methods in existence today, in terms of ease of operation and higher energy efficiency which will afford the outdoor snow/ice centers extended operations periods by preserving the snow/ice for longer periods of time. While the indoor ski centers will enjoy even higher energy efficiency yielding lower operating costs and reduced carbon footprint.

The proposed system can be utilized in new built facilities or for retrofit to existing facilities. Systems in operation today to a great degree have overcome the problems associated with making snow in confined or enclosed spaces or preserving crushed ice for longer periods of time in outdoor facilities.

Present invention proposes to address drawbacks in existing technologies with new and novel methods and to provide equipment to overcome problems for both indoor and outdoor snow and crushed ice facilities through much better preservation, energy efficiency and ease of use.

In order to reduce the size and significant energy consumption of refrigeration means which would be necessary at times of ice or snow making and to cool the indoor envelope during the snow making periods the present invention proposes to shift the high cooling load to the thermal storage unit, thereby, shifting the electrical consumption to off peak hours to take advantage of lower electricity rates. The capacity of the thermal storage means will be significantly greater than that the rate of cooling for snow or ice base as well as indoor air in the envelope which can be significantly greater than the nominal capacity of the refrigeration means by utilizing the huge stored cooling capacity of the thermal storage means, equipment size can be reduced for much lower equipment startup costs and better efficiency.

Since during periods of snow or ice making the cooling requirement is significantly higher than periods of non-snow/ice making, to keep up with the peek demand the thermal storage means is sized to match the cooling capacity of the refrigeration means which in turn is matched to peek cooling requirement during snow or ice making, since the cooling requirement is high during the snow and ice making operations. By employing the thermal storage unit of the proposed invention the equipment size in practice of the refrigeration means can be reduced to 1/10 to 1/30 of the maximum cooling requirement.

In one aspect of the invention, a mass of thermally conductive material is mixed in with a good thermally insulating material, the thermally conductive material having high specific heat and high thermal conductivity while the thermally insulating material having a low specific heat and low thermal conductivity. Essentially the thermally conductive material can absorb any heat in the thermal storage medium, than transmit the absorbed heat into the coolant running through the embedded coolant lines while the thermally insulating material can keep the thermal storage medium well insulated by keeping the outside heat out of the thermal storage medium, thereby, resist heat transfer and build up in the ice, thus resist melting for a longer period of time, in most, case typically up to 2 to 3 times longer than regular ice or ice and aluminum oxide mix only.

In yet another embodiment a large mass of coolant or ice slurry mixed in with a good thermal conductor or a good thermal insulator mixed in individually or together, to absorb heat and to insulate can also be used.

In another aspect of the invention, any convenient form can be taken by the thermal storage means of the proposed invention. The refrigeration means, utilizes a good (single phase or a dual phase coolant, such as ice slurry) secondary coolant, for example Ethylene glycol, which is cooled by a refrigeration unit by running the coolant' through a heat exchanger refrigeration cycle, once sufficiently cooled the coolant is then used to cool a mass of thermally conductive material mixed in with a good thermally insulating material, whereas, the thermally conductive material having high specific heat and high thermal conductivity while the thermally insulating material having a low specific heat and low thermal conductivity. As already discussed the thermally conductive material can absorb any heat in the thermal storage medium, than transmit the absorbed heat into the coolant running through the embedded coolant lines while the thermally insulating material can keep the thermal storage medium well insulated by keeping the outside heat out of the thermal storage medium, thereby, resist heat transfer and build up in the ice, thus resist melting for a longer period of time, in most, case typically up to 2 to 3 times longer then regular ice or ice and aluminum oxide mix only. Alternatively a relatively large mass of coolant or ice slurry can be employed which can act as the thermal storage medium.

In another embodiment instead of running a good coolant i.e. Ethylene glycol through the cooling lines, a good phase changing coolant like ice slurry can be employed. Ice slurry has greater heat absorption compared with single phase refrigerants (Brine) because the melting enthalpy (latent heat) of the ice is also used, making ice slurry a dual phase and a much more efficient refrigerant. Typically a single phase refrigerant is about 45% efficient as opposed to ice slurry which is a dual phase refrigerant and is about 70% efficient.

When the thermal storage means utilizes a mass of material, the material is super cooled by the coolant and this material can form a base on which a layer of snow, crushed ice or ice crystals (in dry form) used in ice slurry are deposited to keep the snow or ice cooler much longer.

In a preferred embodiment, the coolant from the refrigeration means is passed through in heat exchanger piping contained within the mass of the material of the thermal storage medium so maximum heat transfer takes place during charging of the thermal storage medium and in reverse order transfer of maximum cooling, from the thermal storage unit to the snow making equipment and the building envelope, during snow, ice, micro crystals ice or ice slurry making periods.

For skiing and other winter sport activities the base can be inclined to the horizontal using pillars to provide a surface on with snow or crushed ice can be deposited. The mass of material can include a good thermal conductor like aluminum oxide and good thermal insulator like cellulose fiber material (alumina and saw dust or cotton fiber) or a thermal insulator by itself in particle form, bound by ice or other binding agents or contained within other solid materials such as cement to provide a solid base. The area in between the pillars can be utilized for storing the thermal storage means or equipments.

This significant mass of material thereby, in the thermal storage unit ensures that a super cold base is provided for the snow or crushed ice or micro ice crystals to be deposited on, in order to help prevent it from melting for longer periods of time by providing constant super cooling to the snow, ice or micro ice crystals from underneath.

In another embodiment of the present invention, the base can be made of insulating materials to help the snow or ice or micro ice crystals from melting while the location of the thermal storage mass my be elsewhere.

The air within the interior envelope must be kept cool and dry during snow making periods, ideally the humidity level should be less than 100% preferably between 85% to 95% relative humidity and an envelop temperature of between −2° C. to −15° C., depending what type of snow is desired to be made.

It may also be desirable to cool and dry the air using the significant stored cooling in the thermal storage medium as opposed to cooling and drying it using refrigeration means and dryers. It would also be desirable to pre cool and optionally dry the air as well as pre-cool the water before each is introduced into the lines directed to the “snow guns” sprayers for snow and ice making.

The snow generation/production can take place by pre chilling water by thermal storage or refrigeration means, preferably by thermal storage means, which can then be routed to snow making gun's mixing chamber to be mixed with, ideally pre-cooled compressed air or high pressure air and then discharge through spray nozzles in the snow gun. Water droplet coming out through the nozzles can than turn into a very fine mist sized droplets, turning into snow flakes in flight before being deposited into the snow surface.

In preferred embodiment of the present invention, air and water can be discharged through separate discharge nozzle, causing misting of the water droplets just outside the snow gun and then the fine mist can turn into ice or snow crystals in flight, depending on the configuration of the snow guns.

In preferred embodiment of the present invention, ice nucleators can be added in the water to facilitate rapid formation of snowflakes or ice, possibly at higher temperatures.

In yet another aspect of the present invention, the temperature of the indoor envelope during snow or ice making periods is kept at −2° C. to −15° C., and humidity level of less then 100% but ideally 85% to 95%, causing the water droplet exiting the spray gun nozzles to freeze and turn into snow flakes in flight, eventually landing on the super cold thermals storage unit. During snow making periods relative humidity will rise, due to the latent heat of fusion, for this reason humidity levels must be reduced before snow making operations are commenced other wise instead of making a lot of snow or ice a lot of slush would be made.

In a preferred embodiment the air conditioning of the interior envelope may also be provided by thermal storage means instead of refrigeration means to maintain the envelope at below freezing point especially during intervals between snow productions.

In yet another aspect of present invention, for outdoor slopes ice making, thermal storage means can pre-chill the water used to make ice to just above freezing point, thereafter, thermal storage means can supply cooling to the ice making plant to turn chilled water into ice with out engaging any refrigeration equipment.

Typically for every 1° F. drop in temperature 1 Btu/h of heat must be removed from 1 lbs of water, so for example water temperature at 70° F. to be cooled down to 32° F. liquid water will require Example 70−32=38 BTU/h. Thus requiring the removal of 38 btu/h to achieve the temperature drop of 32° F., moreover to achieve the phase change of water at 32° F. to ice at 32° F. 144 btu/h are required, this being the latent heat of fusion of ice must be removed from every pound of water, taking both example together, 144+38=182, to freeze water at 70° F. to 32° F., 182 Btu/h of heat must be removed from each pound of water. This temperature drop, and phase change, can be achieved without any refrigeration means as the proposed invention aims to pre chill the water, and effect the phase change, using the thermal storage means translating in significant energy savings.

The noted example relating to 1 lbs of water seem insignificant, however when considering the snow and ice making requirements of snow centers where up to 40 to 60 tones of snow/ice may be manufactured in one night over a 3 to 4 hour period, the advantages of shifting the cooling load to the thermal storage unit become quiet apparent with significant savings in electrical consumption and its associated costs, and significantly improved commercial viability and a huge reduction in carbon foot print of the facility.

Depending on the method used to make the ice or ice micro ice crystals once made, it can then be scraped or crushed and subsequently blown through insulated delivery lines onto the ski slope without engaging the refrigeration equipment to provide the cooling.

Alternatively coolant in the heat exchanger in the thermal storage means or the refrigeration mean can be run through ice crystals generating machine making tiny spherical ice crystals which can then be deposited on the ski slope and thermal storage unit in place of crushed ice. Ice crystals in the form of millions of spherical micro crystals having a size of 0.1 mm to 1 mm, can be used in place of crushed ice. Due to its round shape and small size these ice crystals can be packed much tighter as opposed to crushed ice having irregular shape and much bigger size. Due to much denser packing properties, this ice can retain much better and even cooling—unlike other irregular shaped ice which mostly conducts heat through the air, the round shape of the ice crystals enables them to flow freely around each other, filling all air pockets to uniformly maintain direct contact with each other, thus the desired low temperature are preserved for much longer periods as compared to crushed ice used currently in snow centers.

The cooling means ideally includes thermal storage means or the thermal storage unit, which is preferably maintained at −10° C. to −35° C. (−14° F. to −31° F.) ideally at −30° C. (−22° F.) for outdoor centers and, conveniently at about −7° C. to −30° C. (−19.4° F. to −22° F.), but ideally at −25° C. (13° F.), for indoor centers. During snow making periods temperature of the thermal storage means rises as cooling is drawn from it and supplied to the enclosed building envelope to make snow indoors, while the drawn cooling for outdoor centers is used to chill water which is than used to make ice, micro ice crystals or ice slurry. The refrigeration means through which thermal storage means is cooled has a significantly smaller refrigeration capacity than the very high cooling demand of the system required during snow or ice making, cooling the air inside the building envelope or to make snow or ice. To satisfy the huge cooling load thermal storage means supplies the cooling as opposed to the refrigeration means.

Specific to an outdoor ski slope, ice skating rink or an outdoor winter wonderland areas just above the snow surface the temperatures can be maintained significantly below the ambient temperature to preserve the snow or ice and to give winter feelings to the patrons. In order to do this, the present invention proposes employing evaporative cooling. By employing, evaporative cooling, essentially a virtual envelope just above the snow/ice surface can be created, having a temperature significantly lower than the ambient air temperature. High, medium or low, pressure, misting, atomizing or flash evaporation/atomizing nozzles, can be employed to discharge, chilled water, above and around the surface of the snow/ice, typically it would be ideal to place the evaporative nozzles about 8 to 10 feet more or less, above the snow/ice surface. The resultant cooling through evaporation is detailed as a following example.

Ambient air temperature at 70° F. and at relative humidity of 30% the cooling effect of the flash evaporative cooling system can be determined using a Psychrometric Chart, refer FIG. 7. for a dry bulb temp of 70° F. and a 20% humidity, the wet bulb temp can be read of the chart, which is 50° F., so 70−50=20, as illustrated in the example a 20° F. drop in temperature due to evaporative cooling alone is possible, without the use of any refrigeration means and without the use of the thermal storage unit.

Depending on the regional climate, in dry arid regions like Arizona for example, with an ambient temp or 100° F. and humidity of 10% a temp drop. of 37° F. can be realized essentially yielding a resulting temperature of 63° F., without the use of any refrigeration means. The resulting evaporative cooling thus can reduce the temperature above the ice surface by as much as 20° F. to 37° F., the virtual lower temperature envelope, created with the aid of evaporative cooling around the slope, will in turn help preserve the ice for much longer periods of time and mitigate the effects of ice loss due to evaporation.

Almost all evaporative cooling system use water at or close to the ambient air temperatures, due to having an abundant of free cooling the water for the evaporative cooling system employed by the proposed invention can be pre-cooled to just above freezing, say 1° C. (33° F.) as having water exiting the evaporative cooling nozzles at such low temperature will have much higher heat absorption capacity than water at ambient temperatures, thereby, rendering an even greater drop in temperature over the snow/ice surface, much further than the above examples.

Polarity of evaporator nozzles placed above the slope or snow/ice area of say 200×80 feet in a grid pattern of say 1 nozzle for every 5×5 feet square will yield a total of 640 nozzles over the entire slope. At a discharge rate of 1 lb/h of water per nozzle will have a combined discharge rate of 640 lbs/h of water. 1 lbs of water thus discharged, has a potential evaporative cooling power of 890 Btu/h/lbs, at 95° F.

So 640×890=569,600.00 btu/h of cooling, representing 47.5 tones of refrigeration capacity every hour without the use of any refrigeration means over the entire snow/ice area. All of this, cooling is based on water being sprayed at close to ambient air temperature. The use of chilled water will yield much higher tonnage of cooling with lower temperature over the slope.

Secondary benefit of this system will mitigate the loss of ice, due to evaporation, as the transition air will be at or near the saturation point above the slope, thus preventing, ice volume lost due to evaporation, in high wind conditions, which contributes to significant amount of ice losses.

Daily grooming of the snow or ice surface can result in large quantities of waste snow, ice and melted ice water. To recycle the resulting snow back to water instead of applying energy intensive heat or spray of hot water to melt the snow/ice, as is done with current systems, it is proposed that a spray of freezing point depressing agent or FDP can be applied over the collected waste snow, this can essentially turn the waste snow or ice into liquid while dropping the temperature of the resulting liquid by as much as 40° F. to 100° F. resulting in a super cold liquid which can then be used for various cooling purposes. After maximum amount of cooling is extracted, eventually the liquid can be run through liquid to liquid separators or filters to separate the freezing point depression agent from the water, ideally recycling both liquids to be used over again. Essentially a quantity of waste ice having 1 Tone of cooling at −2° C. can be turned into super cold liquid having, many more Tone of stored cooling after application of FDP, in most cases by as much as 40 to 80 times. All of this free cooling can then be used as a secondary yet very valuable source to satisfy cooling load of the facility.

In a preferred embodiment of the present invention, the super cold liquid can be utilized for ice/snow making.

In another preferred embodiment of the present invention, the super cold liquid can be utilized for evaporative cooling system.

In yet another preferred embodiment of the present invention, the super cold liquid can be utilized as a secondary thermal storage mean.

Another aspect of the invention is that one or more aspects or implementations as mentioned herein may be combined in one or more ways to perform the invention.

The other features and advantages of the invention will be apparent from the following description and the appended claims.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1, is a sectional side elevation view of an indoor ski slope.

FIG. 2, is sectional side elevation view of an outdoor ski slope.

FIG. 3, is a view of a small section of snow and of thermal storage unit underneath it, showing the heat exchanger cooling pipes, thermal conducting and thermal insulating material comprising of thermal storage means over a supporting surface (inclined ski slope).

FIG. 4, is a schematic view of an evaporative cooling system.

FIG. 5A, is a schematic view of FIG. 1.

FIG. 5B, is same as FIG. 5A, except a micro ice crystals generator and holding tank for ice slurry is shown in this arrangement while ice slurry is being used as the refrigeration liquid.

FIG. 6A, is a view of a waste snow recycling system with a mechanical snow moving tool.

FIG. 6B, is same as FIG. 6A, except mechanical moving tool has been replaced with FDP spray nozzles to move the snow in the chute.

FIG. 7, is a Psychometric Chart Showing thermodynamic properties of gas-vapor mixtures.

FIG. 8, is a chart showing temperatures delivered by evaporative coolers.

DETAILED DESCRIPTION

The following detailed description is of the best currently contemplated mode of carrying out the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims. Selected illustrative embodiments according to the invention will now be described in detail, as the inventive concepts are further amplified and explicated. These embodiments are presented by way of example only. In the following description, numerous specific details are set forth in order to provide enough contexts to convey a thorough understanding of the invention and of these embodiments.

It will be apparent, however, to one skilled in the art, that the invention may be practiced without some or all of these specific details. In other instances, well-known features and/or process steps have not been described in detail in order to not unnecessarily obscure the invention. One should not confuse the invention with the examples used to illustrate and explain the invention. Various inventive features are described herein that each can be used independently of one another or in combination with other features. However, any single inventive feature may not address any of the problems discussed above or may only address one of the problems discussed above and therefore at least a plurality of inventive features disclosed may be required to be considered to address the problems discussed above.

Various embodiments according to the present invention especially with reference to the drawings will now be described herein detail. These embodiments wherever necessary are described with examples and specific details to provide enough contexts for better understanding of the invention and its various embodiments. It will be apparent, however, to one skilled in the art, that the invention may be practiced without some or all of these specific details. The examples used herein are used only for the purpose of illustration and explanation. The features and advantages of the invention may be better understood with references to drawings and description as follows.

The present invention generally provides for a method of making snow artificially within an indoor envelope, the envelop comprising a closed environment including a surface on which the snow is to be deposited, the method comprising: maintaining the temperature of the indoor envelope at lower than −2° C. and humidity level at less than 100% through air-conditioned cooling fans having heat exchanger piping and vent, at least during snow making; introducing pre-chilled water into the lines directed to the snow gun sprayers; pre-cooling and compressing the air by refrigeration means and air compressor respectively, discharging the pre-chilled water and pre-cooled air through spray nozzles of the spray gun into the body of air in the envelop maintained at temperature lower than −2° C. and humidity level at less than 100% causing the water droplet exiting the spray gun nozzles to freeze and turn into snow-flakes in flight. In its preferred embodiment of the invention the humidity levels of indoor envelop is reduced to 85% to 95% before commencing the snow making operations. The temperature of the indoor envelope is maintained at −2° C. to −15° C. In preferred embodiment of the invention, the cooling stored in thermal storage medium is used to provide air conditioning to maintain temperature of indoor envelop below freezing point especially during intervals between snow making. Before discharging the pre-chilled water is combined with pre-cooled and compressed air to form a mixture. The mixture is discharged through same spray nozzle causing misting of the water droplets that turns into ice or snow crystals depending on the configuration of the snow guns. The pre-chilled water and pre-cooled and compressed air are discharged from same spray nozzles. In another embodiment of invention the pre-chilled water and pre-cooled and compressed air are discharged from separate spray nozzles causing water droplets to turn into a very fine mist sized droplets. Ordinarily refrigeration means are employed for chilling the water before being introduced into the lines directed to the snow gun sprayers. In preferred embodiment of the invention, the cooling stored in thermal storage medium is used to chill the water as well as to cool and dry the air. In yet another embodiment of the invention, super cooled water obtained from the recycling of waste snow is used instead of chill water. In its preferred embodiment of the invention, the pre-cooled air is dried before being introduced into the lines directed to the snow guns sprayers. The ice nucleators can be added to the water to facilitate rapid formation of snowflakes or ice even at higher temperatures.

The present invention provides for a system for making snow artificially within an indoor envelope, the envelop comprising a closed environment including a surface on which the snow is to be deposited, comprising: air-conditioned cooling fans consisting of vent and heat exchanger piping for maintaining the temperature of the indoor envelope lower than −2° C. and humidity level to be less than 100%, at least during snow making; Refrigeration means for pre-chilling water before being introduced into the lines directed to the snow guns sprayers; Refrigeration means for pre-cooling the air; Air compressor for compressing the air; and Spray gun for discharging the pre-chilled water and pre-cooled air through spray nozzles into the body of air in the envelop maintained at temperature lower than −2° C. and humidity level at less than 100% causing the water droplet exiting the spray gun nozzles to freeze and turn into snow-flakes in flight. The system is having a thermal insulator layer as a base. The system in one of the embodiment of the invention comprises coolant pipes network embedded directly into snow/ice layer. The system in its preferred embodiment comprises coolant pipes network installed on a profiled surface of the concrete slab, having recessed surfaces filled with mixture of a thermally conductive material with a thermally insulating material to create a mass which is used as base over layer of snow, crushed ice or dry micro ice crystals are deposited. The system in yet another embodiment of invention comprises means for passing the coolant through the coolant pipes of refrigeration unit to cool the mixture as well as water until the water is frozen and mixture is bound by ice and super cooled. Support columns can be used to provide support to the base and for sport and recreational activities the base can be inclined to the horizontal using support columns of varied length. The space in between the support column can be used to locate the refrigeration plant and other control equipments used for running the system. The system in its preferred embodiment of the invention employs thermal storage means as or in place of refrigeration means.

The present invention also provides for a method of creating a virtual envelope just above the snow/ice surface in an outdoor envelope through evaporative cooling system for making snow artificially and retaining it, the envelop comprising a open environment, the method comprising: distributing water through an over head insulated water distribution tank having branch lines for distributing water; Pre-chilling water by refrigeration means to a temperature just above the freezing point to have much higher heat absorption capacity than water at ambient temperatures; introducing the pre-chilled water through the chilled water supply lines into the lines directed to the snow guns sprayers; providing pressure in water lines and spray nozzles through High Pressure pump and discharging the pre-chilled water at high pressure through flash evaporator nozzles of the spray gun into the above and around the surface of the snow/ice to spray fine mist of chilled water in the outdoor envelop to provide flash cooling. The evaporative nozzles are placed about 8-10 feet from the surface of the snow/ice. The air is circulated to speed up rate of evaporation from the flash evaporator nozzles as well as to provide cooling. Fans can be used to circulate the air. The refrigeration means are employed to pre-chill the water. But in preferred embodiment of the invention, the cooling stored in thermal storage medium is used to pre-chill the water. The water is preferably pre-chilled to at least at temperature of 1° C. In yet another embodiment of the invention, super cooled water obtained from the recycling of waste snow is used instead of chill water. The open environment can be covered with a shed like roof with open front and sides and the shed can be used to install the all or any equipment required for functioning of the method hereinabove.

The present invention also provides for a evaporative cooling system for making snow artificially and retaining it within an outdoor envelope by creating a virtual envelope just above the snow/ice surface in the outdoor envelop, the envelop comprising an open environment, comprising: Over head insulated water distribution tank; said over head water distribution tank having branch lines for distributing water; Refrigeration means for pre-chilling water to temperature just above the freezing point to have much higher heat absorption capacity than water at ambient temperatures; Chilled water supply line for introducing the pre-chilled water into the lines directed to the Flash evaporator nozzles; High Pressure pump to provide pressure in water lines and spray nozzles; Flash evaporator nozzles connected with over head water distribution tank for discharging the pre-chilled water at high pressure into the above and around the surface of the snow/ice to spray fine mist of chilled water in the outdoor envelop; pluralities of fan engaged to circulate the air to speed up rate of evaporation from the flash evaporator nozzles and cooling; and at least a controller to control the rate of flash evaporation and activation of flash evaporation nozzles. The system in one of the embodiment of the invention comprises coolant pipes network embedded directly into snow/ice layer. The system in its preferred embodiment comprises coolant pipes network installed on a profiled surface of the concrete slab, having recessed surfaces filled with mixture of a thermally conductive material with a thermally insulating material to create a mass which is used as base over layer of snow, crushed ice or dry micro ice crystals are deposited. The system in yet another embodiment of invention comprises means for passing the coolant through the coolant pipes to cool the mixture as well as water until the water is frozen and mixture is bound by ice and super cooled. The Controller can be a mechanical, electronic or computer device, programmed and connected to various sensors i.e. temperature, wind, humidity sensors to make the system work automatically. The flash evaporator nozzles can be installed in the snow layer and programmed to pop out and pop in when required. In preferred embodiment of the invention, the system comprises misting nozzles in place of flash evaporator nozzles. The system in its preferred embodiment of the invention employs thermal storage means as or in place of refrigeration means.

The present invention also provides for a method for preserving snow by resisting the heat transfer build up in ice within an envelope to elongate the melting period of snow, providing embedded coolant lines of coolant pipes arranged evenly apart preferably at a spacing of 1-1.5 meters.; passing a cooled coolant through the embedded coolant lines of refrigeration unit capable of absorbing the heat from the thermal storage medium through thermally conductive material and transmitting the absorbed heat into the coolant; cooling and drying the air within envelop to bring down the humidity level by air conditioning means. The mixture is used as a base over which layer of snow, crushed ice or dry micro ice crystals are deposited. The ice crystals of size 0.1 mm to 1 mm are used. The depth of the snow/ice layer is preferably kept between 250 mm to 900 mm thick. In one of the embodiment of the invention the coolant pipes network is embedded directly into snow/ice layer. In preferred embodiment of the invention the coolant pipes network is installed on a profiled surface of the concrete slab, having recessed surfaces. The recessed area and area around the recessed surfaces is filled with mixture of a thermally conductive material such as aluminum oxide in granular form with a thermally insulating material such as cellulose fibre material in combination of alumina and saw dust or cotton fibre, to create a mass wherein the thermally conductive material is capable of absorbing any heat from the thermal storage medium to transmit it further and the thermally insulating material is capable of keeping the thermal storage medium well insulated by keeping the outside heat out of the thermal storage medium. Water is added to the mixture and is frozen by the coolant in the coolant pipes until the mixture is bound by ice and super cooled. Ethylene Glycol or Single phase coolant i.e. Brine is used as coolant. The coolant is coolant is cooled by passing through a heat exchanger refrigeration cycle. In yet another embodiment of the invention phase changing coolant such as ice slurry is used as coolant. In yet another embodiment of the invention, a thermal insulator material is made a base below the concrete slab. The thermal insulator material is particle form bound by ice or other binding agents or contained within other solid materials such as cement to provide a solid base. Over this solid base layer of snow, crushed ice or dry micro ice crystals are deposited. In its preferred embodiment of the invention the humidity levels of air is dried to bring humidity level to 85% to 95%. The air is cooled to a temperature ranging between −2° C. to −15° C. In preferred embodiment of the invention, the cooling stored in thermal storage medium is used to provide air conditioning i.e. cooling and drying the air. In one of the embodiment of the invention the thermal storage medium comprises of large mass of coolant or ice slurry.

The present invention also provides for a waste snow collection and recycling system comprising Waste snow melting tank having at least one inclined Collection Chute for collecting of waste snow and at least one exhaust line for supplying recycled super cool liquid; At least one material moving tool to move waste snow from at least one collection chute into waste snow melting tank; Storage tank having supply line connecting to series of spray nozzles; Spray Nozzles located at top of tank through which the Freezing point depressant agent is sprayed to waste snow; Mixing paddles at bottom of tank to speed up change in phase; and Pump to take away super cold liquid via exhaust line. In another embodiment of the invention the pump may be located outside the waste snow melting tank. In one of the embodiment of the present invention, the system comprises at least one material moving tool to move waste snow from collection chute into waste snow melting tank. In yet another embodiment of the invention the system comprise plurality of spray nozzles installed in collection chute to spray FDP on waste snow to partially melt waste snow to enable it to pass through the incline chute easily due to better flow properties and gravity. The system comprises liquid separators to extract FDP from the liquid after cooling is extracted from such liquid.

The present invention also provides for a method of waste snow collection and recycling comprising: Collecting waste snow in a waste snow melting tank through at least one inclined Collection Chute; Moving the waste snow from the chute using material moving tool into waste snow melting tank; Delivering Freezing Point Depressant agent from a storage tank to spray nozzles through supply line connecting series of spray nozzles; Spraying the Freezing Point Depressant agent over waste snow through spray nozzles located at top of tank causing the snow or ice to turn to liquid; Rotating the mixing paddles at bottom of tank to speed up change in phase from solid ice or, snow to liquid; Taking away super cold liquid from tank via exhaust line through a pump. In another embodiment of the invention the pump is located outside the waste snow melting tank. The waste snow can be moved from collection chute into waste snow melting tank through a material moving tool. In another embodiment of invention plurality of spray nozzles installed in the collection chute sprays FDP on waste snow to partially melt waste snow enabling it to pass through the incline chute easily due to better flow properties and gravity. The super cold liquid can be used for snow making and as thermal storage mean. The FDP is extracted from the liquid through liquid separators after cooling for any further use.

Various embodiments according to the present invention will now be described herein detail with reference to drawings. These embodiments are described with examples wherever applicable and specific details to provide enough contexts for better understanding of the invention and its various embodiments. It will be apparent, however, to one skilled in the art, that the invention may be practiced without some or all of these specific details. The examples used herein are used only for purpose of illustration and explanation. The features and advantages of the invention may be better understood with references to drawings and description as follows.

Now referring to FIG. 1, a drawing of an interior building envelope is shown in which snow or ice is to be produced for recreational purposes. The building can conveniently be of any size and shape, ideally a rectangular or tubular configuration but spherical or cylindrical shape may also be build. In this illustration the building is shown at 100 with snow making equipment installed inside. A dividing inclined concrete slab 105 cuts the interior space into top and bottom sections, section above the slope and snow 101 defines the interior air envelope that is to be maintained ideally at below zero degrees Celsius. Flat area at the top of the slope 105 is shown at 105A while bottom flat area is shown at 105B. 105, 105A and 105B being the surface of the slope to be covered with snow or crushed ice.

Below the concrete slab is an insulating layer 110, insulation could be any good conventional insulating material or a super insulator like Aerogel™ or any other engineered or natural insulator or a combination thereof. While above the concrete slab is the thermal storage means 115 comprising of heat exchanger piping network, a good thermal conductor mixed in with a good thermal insulator (natural or engineered) bound together by ice, ideally the thermally conductive material used can be aluminum oxide in granular form, while saw dust can be a good thermally insulating material, or an engineered material with a good thermal conductor and a good thermal insulator mixed into together and bound by ice. Above the thermal storage unit 115 and resting on it is a snow or crushed/granulated ice layer 120. In the lower section of the concrete slope 105 is an equipment room 130 containing refrigeration plant along with other control equipment, alternatively the equipment room can be placed elsewhere in the building or outside the building. Supporting the concrete slope are series of support columns 135A and 135B. A chair lift system is shown at 140 taking skiers to the top of the slope, while an area of winter wonder land and an alpine café is shown at 145 along with a hotel 150 at the base of the slope 105B with hotel room balconies at 155 overlooking the winter wonder land 145. An area containing food court and observation area is shown at 160. A series of snow or ice making snow guns are evenly arranged as shown at 165, each gun strategically located to produce and deposit the snow evenly over the slope 105, 105A and 105B, alternatively snow making machines may be located on the walls or the floor level, while a series of A/C cooling fans are shown at 170 comprising of vent and heat exchanger piping to supply cool air to the envelope. Series of light fixtures are shown at 175.

At the bottom of the slope 105B is a gully/chutes 180 for collection of waste snow. After passing through chutes 180, waste snow is deposited into waste snow recycling and melting tanks 185.

FIG. 2, is same as FIG. 1, except it depicts an outdoors snow or ice slope 200 having no air conditioned interior envelope. The slope may be covered or uncovered having a shed like roof with open front and sides.

In this depiction the concrete slab 105 is conveniently located on ground level, on a prepared slope made of an artificial incline as shown at 230 while the roof structure of the slope is shown at 220 with a series of support columns 225. All systems are identical to FIG. 1, except for the following items being added while envelope air conditioning items 101 and 170 have been deleted. 420 and 425 are over head water distribution trunk and branch lines for the evaporative cooling system installed to cool the area 201 above the slope 105, 430 are individual flash evaporator nozzles used to spray pressurized chilled water ideally but not necessarily at or near 0° C. (32° F.) to flash cool the air above the snow or ice surface, whereby, the resulting cooler ambient air temperatures facilitate retarding the melting and loss of ice due to high temperatures and evaporation of snow or ice layer 120. In addition to or alternatively flash evaporative system can be installed just under the snow layer 120 (not shown) similar in fashion to automatic lawn sprinklers, flash evaporator nozzles can pop out as needed to spray chilled water under high pressure to spray fine mist of chilled water just above the surface of the snow/ice layer 120 to provided flash cooling, thereby, dropping the temperature which can help resist or prolong the melting of the snow or ice layer as a result of lower temperatures. 215 are a series of fans that can be engaged to move the air to speed up rate of evaporation from the flash evaporator nozzles and subsequent cooling if there is no wind present. The rate of flash evaporation and activation of flash evaporator nozzles can be controlled by a controller, the controller can be mechanical or electronic or can be a computer, monitoring and controlling various aspects of the facility, thereby, allowing the system to be automatically controlled. Various operations can be started or shut down by programming of the controller which can be hooked up to various sensors, i.e. temperature, wind, humidity etc., as well as when and at what speed the fans are to be operated under various weather conditions, during no or little wind conditions, this will ensure that there is no buildup of high humidity levels above the slope, if the air becomes stagnant, with the accompanying high levels of latent heat.

Wind, temperature, wind and humidity sensors can be connected to the controller to activate various components of the flash evaporator system. Alternatively in place of flash evaporators, misting nozzles may also be used.

Water at standard ambient temperature used for flash evaporative cooling can drop the temperature by as much as 10° F. to 37° F. depending on temperature, wind and humidity. However, if chilled water at or near 0° C. is used in place of water at ambient temperature than the resulting drop in temperature can be significantly greater, as chilled water has much higher heat absorption, capacity. Since there is an abundant of stored cooling in the thermal storage means 115 water can be chilled by using a very small amount of that stored cooling for flash evaporative cooling without the need for expanding additional energy to chill the water by running power hungry refrigeration unit.

FIG. 3, is a close up of a section of ski slope 105 showing the thermal storage means, supporting surface, insulation and snow layer, several coolant pipes 305 are shown that make up the heat exchanger piping of the thermal storage unit. Ideally coolant pipes are arranged evenly apart denoted by “w”, ideally at a spacing of 1 to 1.5 meters apart, dictated by the size of the pipes and parallel to one another and perpendicular to the length of the slope 105, running over the entire length of the slope from top to bottom. Coolant pipes are embedded in mixture of thermally conductive and thermally insulating material, such material comprising of (activated alumina) aluminum oxide in granular form and wood saw dust laying on a flat surface, bound together with ice 115. Alternatively the mixture of aluminum oxide and saw dust (thermal conductor and thermal insulator) may be bound with cement this may be in a mixing ration more of less, in the range of 9% to 40% by volume.

In another embodiment the coolant pipes network 305 can be installed on a profiled surface 310, of the concrete slab 105, having recessed surfaces, there as the pipes can be located in the said surfaces. The recessed area and area around the recessed surfaces can be filled with mixture of alumina and saw dust. Thereafter, water can be added and frozen by the coolant in the coolant pipes until the fixture of Alumina and saw dust are bound by ice and super cooled. Snow or ice is formed and deposited on surface of thermal storage unit 115, snow/ice 120 is kept cool by surface of 115 which in turn is kept cool by coolant pipes 305, resting on concrete surface 105 that in turn is insulated by insulation 110. Depth of the snow is represented by “d”.

Alternatively, piping 305 imbedded in alumina and saw dust mixture bound by ice or alumina and saw dust mixed into concrete slab may be eliminated and cooling pipes may be directly embedded into snow/ice layer to keep it cool.

“i” represents isothermals that from in the snow, these are points of same temperature within the snow which, if uneven, will give rise to portions of the snow which are of too high a temperatures that may cause band of snow with uneven consistency in part of the snow layer. To avoid this problem the coolant lines under the snow have to be arranged so as to distribute cooling as evenly as possible to ensure that an even snow/ice quality is maintained throughout the snow surface, the arrangement in FIG. 3, is intended to achieve the stated goals by evenly distributing the cold temperatures while preventing heat transfer through a thermally conductive layer as well as a thermally insulating layer which are formed of alumina and saw dust embedded in ice.

Ideally, the depth of the snow/ice layer is of a thickness of 250 mm to 900 mm (9.8 in to 35 in), as this depth of snow/ice can be ideal to maintain the temperatures on the surface to maintain the desired quality of the snow/ice on the surface.

FIG. 4, is a schematic view of a simple flash evaporative cooling system. Now looking at the drawing, 400 is a chilled water supply line to the evaporative cooling insulated water supply tank 405, 410 is a high pressure pump attached to main supply line 415 which in turn feeds trunk lines 420A, 420B etc. 425-1, 425-2 and 425-3 etc, are series of branch lines to which evaporative nozzles 430s are attached, the fine mist coming out of 430-1, 430-2, 430-3 etc., is depicted by 435-1, 435-2, 435-3 etc. High pressure pump 410 is necessary to provide enough pressure in the water lines and the spray nozzles 430 to cause the water coming out of the same to come out with adequate force to create a rapid and fine mist so flash evaporation takes place.

FIG. 5A depicts a schematic view of FIG. 1 an A/C evaporator is shown at 520 while the condenser for the A/C unit is located outside the building and is not shown, in the drawing. A primary thermal storage unit is shown at 115, comprising of cooling supply lines grid 305. Thermal storage unit comprising of a good thermal conductor, a good thermal insulator, each in 5 to 50 percent by weight, ideally 5% to 15% each by weight, more of less as desired, bound together by ice. Thermal storage means 115 is ideally kept at −10° C. to −35° C. (14° F. to −29° F.), cooling is draw from the thermal storage unit as needed to cool the building envelope and to satisfy other cooling requirements by supply line 522A, after running the coolant through a series of air handling units 170 to cool the building envelope the spent coolant starts its return journey via return lines 522B back to the thermal storage unit via the A/C unit 520, to be cooled for another return trip to air handling units. During periods of charging the thermal storage unit, the coolant is cooled by the A/C unit so it can take away the built up heat from the thermal storage unit. While during normal operation and especially during periods of snow making periods, cooling is drawing from the thermal storage means.

Typically under normal operations of an indoor center, assuming thermals storage unit has been fully charged and sufficient snow cover is present, the number of hours used by each cycle would be as follows.

Snow Making Period  4 hours Facility use by patrons  16 hours Snow grooming/Maintenance 2.5 hours Conditioning the air in the building envelope 1.5 hours

In the example above it is clear that 20 hours is provided for the thermals storage means to be charged by the A/C unit.

Any water used for snow/ice making can be chilled by the thermal storage means, alternatively the same water can be chilled by the secondary thermal storage means.

A secondary thermal storage unit is shown at 525 while a series of coolant heat exchanger grid lines located inside 525 are shown at 526. Coolant is supplied for various needs by supply line 526A, after the coolant passes through air handling units 170 it is returned via return line 526B to be recharged by the secondary thermal storage unit 525, thereafter, the cycle is repeated as needed. Cooling for the secondary thermal storage unit comes from change of phase of waste snow in the waste snow/ice recycling tank. A natural or preferably engineered freezing point depressing agent (FDP) or a combination of the two, having an eutectic temperature of −60° F. to −100° F. is sprayed inside the waste snow/ice recycling tank 185, causing the snow/ice to turn into liquid, the waste snow having a temperature of −1° C. to −4° C. to undergo phase change, where the resulting liquid can have temperatures in the range of −60° F. to −100° F. By spraying of FPD agent to melt the waste snow instead of hot water, a reasonable amount of energy can be saved which would otherwise be used to heat the water while, an enormous amount of cooling can be realized without the use of any mechanical or electrical energy input. All of this stored super cold liquid can then be used as the secondary thermal storage unit. The cycle can be repeated as often as waste snow is collected, this system is a backup source of cooling only, the art may or may not be practiced using the secondary thermal storage unit. In the alternative snow or ice can be made and then deliberately melted by spraying of FPD agents to realize a lot more cooling, which can then be used as needed.

Alternatively return line 526B can be routed through the A/C unit to partially cool the refrigerant liquid before it enters the secondary thermal storage unit grid piping 526.

An air compressor with air drying units is employed at 528. Air compressor 528 can be used to supply compressed air to snow making “snow guns” 165, via supply line 530 while chilled water can be supplied by chilled water supply tank 527. A floor drain is provided at 529.

FIG. 5B, a schematic view of FIG. 1A and FIG. 1B and is nearly identical to FIG. 5A, only those items that are different from FIG. 5A will be discussed here. This embodiment uses ice slurry as the coolant. A micro ice crystal generator to produce ice slurry has been added at 532 which is being supplied cooling from supply and return refrigerant lines 531 coming from the A/C unit 520 (not shown) as shown in FIG. 5A. In place of a single phase coolant like Ethylene Glycol, ice slurry is being produced by micro crystals ice generator 532. Ice crystals scraped and fed into the ice/water or water with a FDP mixed into it, (BRINE) storage tank 533, resulting in ice slurry which in turn is used as a highly efficient dual phase coolant to charge the thermal storage unit during charging periods between snow making operations. While during snow making periods the same coolant can take cooling from the thermal storage means and supply it to the building envelope to facilitate snow making. Cooling can and ideally is provided to the building envelope for air conditioning purposes during non snow making periods also from the thermal storage means.

Now looking at FIG. 6A, a waste snow collection and re-cycling system. 810 is the waste snow or ice collected in a collection chute 180, 815 is an auger type material moving tool to move waste snow from collection chute 180 into waste snow melting tank 185. Inside the tank 185 are a series of spray nozzles 825 used to spray freezing point depressing (FPD) agent onto the waste snow 810, causing it to change phase from solid to liquid. Spray nozzles 825 being fed by supply line 820 form FDP agent storage tank (not shown). Spray of FDP can cause the snow or ice to turn to liquid while its temperature can drop by as much as 50° F. to 100° F. depending on the type of FDP used and it's eutectic temperature, thereby, increasing the stored thermal capacity of the resulting liquid by as much as 50 to 100 times. For example 1 ton of waste snow or ice having 1 ton of cooling capacity in its solid form will result into 100 tons of cooling capacity after change of phase into liquid form; the resulting liquid can then be used to provide super cooling for various purposes, including air conditioning. As 825s spray FDP onto 810, mixing paddles 830 help in speeding up the change of phase of 810 by mixing of the two. 835 is the resulting super cooled liquid at the bottom of the tank 185, pump outside the tank take away the super cold liquid via exhaust line 840 to be used in the second thermal storage unit or for direct cooling where cooling is needed. Once all the cooling is extracted from the liquid 835 it can then be put through liquid to liquid separators where the FDP is separated from water while each is sent to their respective holding tanks for another cycle.

Alternatively as depicted in FIG. 6B, instead of using a material moving device 815, FDP spray nozzles can be placed in the chute 180 to partially melt the waste snow there by making is pass through the inclined chute easily due to better flow properties and gravity.

FIG. 7, is a Psychometric chat showing physical and thermodynamic properties of gas-vapor mixtures and resultant temperature delivered by flash evaporative coolers, this chart depicts yield rates for water at ambient temperature. The proposed system can use chilled water at or near 0° C. there by yielding much lower resulting ambient temperatures as chilled water can have much better heat absorption. The water can be pre-chilled by routing it through super cold thermal storage unit storing an abundant of cooling.

FIG. 8, is a chart showing temperatures delivered by an evaporative cooler, looking at the chart at an ambient temperature of 90° F. and a relative humidity of 15%, an evaporative cooling system can drop the temperature down to 69° F. a difference of 21° F. without the used of an A/C unite.

Any or all components of the proposed technology can be used for thermal storage to be used for any and all A/C or refrigeration purposes other than indoor or outdoor snow/ice centers. The proposed technology can also be used exclusively to provide thermal storage for building, industrial application or for any other type of air conditioning and refrigeration purposes.

In the above description of the above embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is known by way of illustration a specific embodiment in which the invention may be practiced. It is to be understood that other embodiments may be utilized or combinations, thereof, and structural changes may be made without departing from the scope of the present invention. It is also to be understood that certain components or technologies can be added or deleted without departing from the scope of the present invention.

While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised within the spirit and scope of the invention.

It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims. 

What is claimed is:
 1. A method of making snow artificially within an indoor envelope, the envelop comprising a closed environment including a surface on which the snow is to be deposited, the method comprising: maintaining the temperature of the indoor envelope at −2° C. to −15° C. and humidity level at 85%-95% through air-conditioned cooling fans having heat exchanger piping and vent, at least during snow making; introducing pre-chilled water into the lines directed to the snow gun sprayers; pre-cooling and compressing the air by refrigeration means and air compressor respectively, discharging the pre-chilled water and pre-cooled air through spray nozzles of the spray gun into the body of air in the envelop maintained at temperature lower than −2° C. and humidity level at less than 100% causing the water droplet exiting the spray gun nozzles to freeze and turn into snow-flakes in flight.
 2. The method of claim 1 wherein before discharging the pre-chilled water is combined with pre-cooled and compressed air to form a mixture.
 3. The method of claim 2 wherein the mixture is discharged through same spray nozzle causing misting of the water droplets that turns into ice or snow crystals depending on the configuration of the snow guns.
 4. The method of claim 1 wherein the pre-chilled water and pre-cooled and compressed air are discharged from separate spray nozzles causing water droplets to turn into a very fine mist sized droplets.
 5. The method of claim 1 wherein the cooling stored in thermal storage medium is used to chill the water and to cool and dry the air.
 6. The method of claim 1 further comprising the steps of adding of ice nucleators in the water to facilitate rapid formation of snowflakes or ice even at higher temperatures.
 7. A method of creating a virtual envelope just above the snow/ice surface in an outdoor envelope through evaporative cooling system for making snow artificially and retaining it, the envelop comprising a open environment, the method comprising: distributing water through an over head insulated water distribution tank having branch lines for distributing water; Pre-chilling water by refrigeration means to a temperature just above the freezing point to have much higher heat absorption capacity than water at ambient temperatures; introducing the pre-chilled water through the chilled water supply lines into the lines directed to the snow guns sprayers; providing pressure in water lines and spray nozzles through High Pressure pump and discharging the pre-chilled water at high pressure through flash evaporator nozzles of the spray gun into the above and around the surface of the snow/ice to spray fine mist of chilled water in the outdoor envelop to provide flash cooling.
 8. The method of claim 7 wherein the cooling stored in thermal storage medium is used to pre-chill the water.
 9. The method of claim 7 further comprising the steps of using plurality of fans to circulate the air to increase rate of evaporation from the flash evaporator nozzles and subsequent cooling.
 10. A method for preserving snow by resisting the heat transfer build up in ice within an envelope to elongate the melting period of snow, providing embedded coolant lines of coolant pipes arranged evenly apart at a spacing of 1-1.5 meters, wherein the coolant pipes network is installed on a profiled surface of the concrete slab, having recessed surfaces, the recessed area and area around the recessed surfaces is filled with mixture of a thermally conductive material capable of absorbing any heat from the thermal storage medium, with a thermally insulating material capable of keeping the thermal storage medium well insulated by keeping the outside heat out, and water; passing a coolant said coolant cooled by passing through a heat exchanger refrigeration cycle through the embedded coolant lines of refrigeration unit capable of absorbing the heat from the thermal storage medium through thermally conductive material and transmitting the absorbed heat into the coolant and capable of freezing the water added to mixture until the mixture is bound by ice and super cooled to create a mass, the said mass used as a base over which layer of snow, crushed ice or dry micro ice crystals are deposited; and cooling and drying the air within envelop to bring down the humidity level by air conditioning means.
 11. The method of claim 10 wherein the coolant pipes network is embedded directly into snow/ice layer.
 12. The method of claim 10 wherein ice crystals of size 0.1 mm to 1 mm are used.
 13. The method of claim 10 wherein the coolant is Ethylene glycol.
 14. The method of claim 10 wherein the coolant is a single phase coolant such as Brine.
 15. The method of claim 10 wherein the coolant is a phase changing coolant such as ice slurry.
 16. The method of claim 10 wherein the thermal storage medium comprises of large mass of coolant or ice slurry.
 17. The method of claim 10 wherein the thermal conductor is aluminium oxide in granular form.
 18. The method of claim 10 wherein the thermal insulator comprises of cellulose fibre material i.e. combination of alumina and saw dust or cotton fibre.
 19. The method of claim 10 wherein the thermal insulator is particle form bound by ice or other binding agents or contained within other solid materials such as cement to provide a solid base below the concrete slab.
 20. The method of claim 10 wherein the cooling stored in thermal storage means are used to cool and dry the air. 